Mesenchymal Cells Hold the Key to Immune Cell Recruitment to and Migration within Melanoma

Samaniego et al. (this issue) report on distinct tumor-associated mesenchymal cell (MC) populations in human melanomas. FAP−CD90+ peritumoral MCs may be involved in immune cell recruitment from the bloodstream. FAP+CD90− intratumoral MCs were associated with extracellular matrix fiber deposition, and their numbers correlated with high immune cell infiltration. Thus, different MC subsets modulate the cellular composition of the intratumoral and peritumoral melanoma microenvironment.